One area in the body where soft tissue is surgically reattached to bone is the attachment of a rotator cuff tendon to the humerus. The rotator cuff tendons have areas of low blood supply. With an increased blood supply, a tissue, such as a tendon, can repair and maintain itself better and faster. Thus, areas of poor blood supply in the rotator cuff make these tendons difficult and slow to heal following an injury, such as a tear to the supraspinatus muscle or the subscapularis muscle. In such a tear, part of the tendon is pulled away from the bone. Because of the poor blood supply, rather than attempting to allow an injured rotator cuff to heal on its own, a physician often recommends that the tendon be surgically repaired to better fix the position of the cuff to the bone to prevent further damage and improve the environment for healing. For example, the physician may attempt to fix the tendon to the bone using a retainer such as an anchor. One example of an anchor is disclosed in U.S. Pat. No. 4,741,330 (the Hayhurst patent), which is incorporated herein by reference.
Other areas in the body also have tissue that can be surgically reattached to bone when torn from the bone or can be surgically repaired when a tear forms in the tissue. These areas include, for example, the biceps tendon, the lateral collateral ligament in the knee, the medial collateral ligament in the knee, the meniscus in the knee, the popliteal ligament in the leg, and the labrum tendon in the knee.
Fibrous tissue wounds, such as muscle, ligament, and cartilage tears, can be repaired arthroscopically using sutures. Traditionally, to close a fibrous tissue wound, a surgeon would insert two suture needles into the tissue with sutures attached, thread the sutures across the wound, and then tie knots to fix the free ends of the sutures within the tissue.
To simplify the wound closure procedure and to improve fixation, various types of retainers have been developed. One example of a retainer is disclosed in the Hayhurst patent. In the Hayhurst patent, one end of a suture is fixed to a resiliently-deformable, bar-shaped retainer. The retainer is loaded into the bore of a hollow needle and deployed into or against the fibrous tissue. The surgeon then threads the suture across the wound and tensions a free end of the suture to pull the wound closed. When the surgeon tensions the suture, the bar in the retainer becomes oriented transversely to the suture hole, anchoring the suture in place.